Electric hammer



April'zz, 1930. 1 G. SHOCK 1,755,565

ELECTRIC HAMMER Filed Oct. 2O 1926 Patented Apr. 22, 1930 LAWRENCE e.- sirooK,v on Losf'Aivennns; oanrronn'in ELECTRIC HAMMER- Application ledctober 20, 115215:` Serial iNo. 1452,863.y

This invention relates' to improvements in electric hammers. v

object of'thevinv'ention is toprovide an improved' electric hammer of simple andv dus-frable constructiony inv whichjprecautionaryf measures have beentakenv `against wear` of the various parts and lwherem jmeans 1s provided; for takingfup t-hewear whichY must p tion'10"Ofthe"h'ousing. n

tor-*is indicated at 16. The' drawingfillus- 505 necessarily.y occur upon'worn parts; Y 10' there is a shat'driven'by-the rotor of an electric motor andto provide Va yieldalole'connection betweenfthe shaft andthe'frotorfso' .1.5 Y that shocks imparted i to Vthe shaft will not y be. transmitted to the rotor because ofthe yieldable connect-ion;

Another object ofthe 'invention' is to provide'anv electrichammer wherein there is a SOI-housingl in which is kdisposed an electric motor,V a shaft carrying.: a cam driven'b'ythemotor,'a` tool holdersli'dably mounted upon the housing and having aca-m' adapted kto loe en" gaged loy the mentionedfcam and to provide -Y a spring construction rwhich Yis ladjustable "and which'ser-v'es to urge the Vtool holderinto such"y position that rits cam vwill, normally be heldl disengaged from the cam 'on the shaft' so". that 7in order to cause'the' tool to be hammered.v se it is necessary to forc'ethe'housingotoward` the tool holder overcoming' the action ofthe spring construction.

Withthe foregoing and 'other objectsv in viewiwhich will be made vmanife'stdinthefollowing'detailed description, and specifically' pointed 1ont in the appended claims; refer'- ence is hadto the accompanying..drawing/for an illustrated embodiment of the invention, wherein: Y

Figure 1 is a'vertical, longitudinal section through lth`e"improved electric hammer;

Fig. 2-'is` artransverse section takensuh' stantially upon the line 2*-2 onFigure '1.'

Fig. 3 is a transverseV secti'onitalr'en upon the lined-3,' upon Figure 1.

Another object Iof Vthe inventionfis to' prof vide yan improved electrich'ammer wherein Vwhichis cylindricalv in form',' is indicated at Y10, andchas a cap 11 and a third part' 12 securedl thereto as by screws 13; Y rl-he'third part 12 is provided with.' a tubular eaten'sionle. Nithin the housing there 55.-V is dispos'e'd'an electric` motor, thek iieldior stator" of: which'indicated at 15 is rigidly' mounted upon the interiorof thecenter sec- The'rotofrof the mo` trates l. thef'motor as being a direct/current motor'having lorushesv 17. It will-'of course' loe'V understoodthat any otheri suitable 'type' offniotor-"may beemployed, either 'direct cur'- rent or alternating current. plied "to 'thermotor through al-calole4 18,*con`= trolled by" a switch 19 operahle'by aiin'ger20`y pivotallymount'ed uponV the' handle 21 #which is integral with or' securedfto thecap 11;

"Witliim the housingV there" is disposeda'lm shaft; divi-ded'into vtwo sections :22 and"23.' These sectionsrar'e connectedto eaehlothe'rby' a tongue and "grooveconnection 2112 VVlocated f withintherotor 16.' Thermor-"16 is looselyj y mountedupon. the sha-it" but" is'- capable; of; 75

dispesed"within'tlie tubular eitension' 1li-*and en f two" lnishings 26 'an-d ,'27 'are /inountedzinthe' 'l tubular: "eXtensio'n', yforming bearings forv the shaft'sect'ion. The 'bushingf A may ,he pressed inte orotherwiseI secure'dt'o the tubular exten'- sien whereas thehnshinfg 26 is' pre'ifferalolygv hr'e'aded'into the vti'ibular extension'. AThe cojl'- larj'25 'bears against lthe bushing T263" and-on"v the-'other 'end ofthe shaft section' 22j there. is 1 keyed and pfinnedaj collar 28 'bearing-against thehushing'Q rEhe' collars' 25"'. and 28 be'arl ing against Lthe"bushings 26 "and 27. respec# tively resist 'axialinovement ofithe shaft section 22 Wear" on tliesebiishings can loe- Ytalren nplloy screwing out the bushin'g26'.'

This' AcanL ce iacconeplishedv hy inserting" a-pin J5 there isfrigidlysecured ahcam 32 adapted'to Current is sup- 65 soV engage a cam 33 mounted upon the tool holder 34. rlhe tool holder 34 consists of a tubular body into which the stem 35 formed integral with the cam 33 extends. Within the body forming the tool holder there is formed a shoulder on which seats a hard metal cap 36, having its face concaved complementary to the convexed end of the tool 37 fitting in the body. A diametrical aperture is formed through the tool hol-d-er 34 to receive a wedge 33 and this aperture is so constructed that when the wedge is driven into it that the wedge will be frictionally held in positionV therein. An aperture 39 is formed in the body of the tool 37 and is of such size that the wedge 38 loosely' extends through it. From this construction it will be understood that the tool 37 is loosely. held in the tool holder 34, the wedge 33 serving to merely 1'iold the tool from dropping out of the tool holder. The particular tool employed may be'different under various circumstances; for

example, it may be a chisel, a'punch, a rivet hammer, or any other desirable tool. One tool :an besubstituted for another by indicating the wedgeV 38 and replacing it after the new tool has been placed in the tool holder. The wedge is preferably fastened to the tool holder by a chain 40 to prevent its becoming iost.

An inside sleeve 41 is fastened to the tool holder 34 by a nut or union joint 42 which is held on the tool holder by the shoulder43. rlhis inside sleeve extendsfroni the tubular extension 14 and has longitudinal grooves formed upon its interior surface which receive Vsplines 45 formed on the tubular member 14. ln this manner the tool holder 34 and the sleeve 41 are held against rotation relatively to the housing, but they are capable of sliding longitudinally relatively to the housing. On the exterior surface of the cam 33 there are also formed splines asV 49, fitting in a groove on its exterior surface,

. one end of the split ring being bent radially inward through the sleeve and through an aperture formed in the tubular extension. A similar lock indicated at locks the nut 42 from unscrewing from the inside sleeve 41.V

TENithin the outer sleeve 46 there are arranged two spiral springs 51 and 52, the spring 51 being compressed between the flange 48 and a shoulder on the tubular extension, and the spring 52 being compressed between the flange 48 and a gland 53 threaded into the open end of the outer sleeve 46. The gland 53 has notches upon its periphery in which a leaf spring 54 which is fastened to the outsi de sleeve is adapted to seat; The spring 54 locks the gland 53 from unscrewing but permits it to be tightened or loosened to adjust the compression of the springs 51 and 52.

.The sleeve 46 contains a lubricant and to prevent this lubricant from leaking out of the sleeve, the gland 53 provides a stuffing box 55 which is closed by a packing gland 56 threaded on to the gland 53. The two springs 51 and 52 work in opposition to each other and they normally hold the inside sleeve 41 in suchposition'tiat the tool holder 34 will have its cam 33 disengaged fromI the cam 32. By forcing the Vhousing toward the tool holder, the spring 51 will be further compressed and the twol cams 32 and 33 can be caused to engage.' Normally it is desired that when no pressure is applied to the housing that thetwo camsv32 and 33 just clear each other. In order-.to provide for adjustment and'to take up wear on the engagingv surface of the cams the gland 53 can be tightened or loosened; this provides a very fine adjustment.

Further adjustment can be provided by removing the outside sleeve 46 and taking out or inserting one or more shims 47.

rlhe opposed faces of the collar 25 and the i. most adjacent hub of the rotor 16 are hollow-d out and a spiral spring 57 is disposed about the shaft section 22 and compressed between them. vOn the opposite side of the rotor 16 a collar 53 is secured to the shaft section y23 and the opposed faces of this collar and the most adjacent hub of the rotor are also lhollowed out to accommodate a spiral spring 59. The two springs 57 and 59 work inopposition to each other upon the rotor 16 I v61. The outer race lits upon the interior of thecap 11. The tongue and groove connection 24 is a relatively loose one, permitting a small degree of longitudinal movement of the shaft sect-ion 23 relatively to the shaft section 22. This brake in the shaft is for the purpose of preventing the shaft from pounding out the bearing 60. there should be a small amount of play between the collar 25 and the bushing 26, shocks imparted tothe shaft 22 will not be transmitted to the shaft section 23 so as to pound out the bearing 60 because of this brake 24. The ends of the shaft sections 22 and 23, near the brake 24,

fit snugly within the rotor 16 and are held thereby in alignment so that, although the rotor is loose upon the shaft, it will be held thereby centrally of the stator 15.

The operatio-n of the improved hammer is as follows: rlhe tool 37 is placed against the article to be hammered and by operating the lever 2O the rotor 16 will be caused to revolve, revolving the shaft 22 and the cam 32. The handle 21 is not pressed with sufficient pressure to cause the cams 32 and 33 to engage until the rotor is rotating at a maximum speed, then by forcing thehousing toward the tool holder the cams can be caused to engage so the tool 37 will be `vibrated and hammered. The magnitude of each blow imparted to the tool 3T varies with the pressure applied to the handle 21. rlhe second handle 62 is preferably secured to the housing, assisting in moving the housing about and in holding it in the desired position.

From the above described construction it will be appreciated that a novel electric hammer is provided which cannot easily get out of order for the reason that the wearing parts are adequately protected. Furthermore, the improved hammer may easily and quickly be constructed and in the event that certain parts should require Arepair or replacement it may be easily and quickly assembled to accomplish this purpose.

It will be understood that various changes may be made in the details of the construcsleeve disposed around the housing and on which is formed a flange, springs bearing on opposite sides of the flange and yieldably holding the tool holder in the predetermined position wherein the cams are disengaged, whereby, upon forcing the housing toward y the tool holder, the cams will engage, causing the tool holder to be vibrated by the motor.

2. An electric hammer comprising a housmg, an electric motor in the housing, a shaft driven by the motor, a cam carried by the shaft, a tool holder carrying a sleeve slidably keyed upon the housing, said sleeve having a flange thereon, an outer sleeve secured to the housing and disposed about the first sleeve, a gland threaded into the open end of the outer sleeve, a spring compressed wit-hin the outer sleeve between the flange and the housing, a second spring compressed within the outer sleeve between the flange and the gland, and a cam carried by the tool holder engageable by the mentioned cam.

v '3; Ani electric hammer comprisinga housmg havingi a. tubulary extension," an electric motor in the. housing, a [shaft rotatably mounted in the ti'ibula'rextension and extendcarried by the shaft,ia''tool holderhaving a sleeve rdisposed aboutthe'tubular extension, the said sleeve hav-ing' 'a splinedconnection with thefextension,apcami-carried by the tool ing'. through the rotor of the motor, a cam holder engageable by the first cam, there being a flange on the exterior of said sleeve, an

outer sleeve secured to the housingand disposed about said sleeves, a spring compressed j between the flange and the housing, a gland threaded into the outer sleeve, and a spring compressed between said flange and said v gland, said springs serving to normally hold the tool holder in that position wherein the cams are disengaged.

4;'An electric hammer comprising a housmotor in the housing, a shaft rotatably mounted in the tubular extension and extending through the rotor of the motor, a cam carried by the shaft, -a tool holder having a sleeve` .about said sleeves, a spring compressed between the iange and the housing, a gland threadedv into the outer sleeve, and a spring compressed between said fiange and said gland, said springs serving to normally hold the tool holder in that position wherein the cams are disengaged, there being bushings mounted in the ends of the tubular extension through which the shaft extends, and collars on the shaft bearing against said bushings so as to prevent axial movements of the shaft.

5. An electric hammer comprising a housingv having a tubular extension,` an electric motor in the housing, a shaft rotatably mounted in the tubular extension and extending through the rotor of the motor, a cam carried by the shaft, a tool holder having a sleeve disposed about the tubular extension, the said sleeve having a splined connection with the extension, a. cam carried by the tool holder engageable by the first cam, there being a flange on the exterior of said sleeve, an outer sleeve secured to the housing and disposed about said sleeves, a spring compressed between the ange and the housing, a gland threaded into the outer sleeve, and a spring compressed between said flange and said gland, said springs serving to normally hold the tool holder in that position wherein the cams areA disengaged, there being bushings mounted in the ends of the tubular extension through which the shaft extends, and collars on the shaft bearing against said bushings so ring having a tubular extension, an electric llG as to prevent axial movements of the shaft, the rotor of the motor being loose upon the shaft and having a tongue and groove conneetion With one of said collars, and spring means urging the rotor into a predetermined position upon the shaft.

- In testimony whereof I have signed my name to this specification.

Y AWRENCE G. sHooK. 

